they too have a taste for us. some of us are mosquito magnets. >> we measure how many are trying to bite the person after five minutes. >> reporter: researchers lindsay balony turns mosquitoes loose on volunteers' bare arms. >> and we're off. reporter: the mosquitoes really like the way this guy smells. look how they're trying to push through the little screen. scientists have yet to pinpoint what drives them wild. but there's evidence that people with higher levels of sugar in their blood can be more and tieing to a hungry mosquito who can typically smell dinner 50 yards away. >> they're not working off very much, but they do it so so well. in some way i've developed a weird kind of respect for the mosquitoes. >> reporter: the centers for disease control have respect for mosquitoes too. the agency was created in 1946 to fight malaria. while malaria has been all but wiped out in the united states, there were more than 700 reported cases of west nile virus here last year alone. so in places like fairfax county, vir